Communication networks are well-known in the computer communications field. By definition, a network is a group of computers and associated devices that are connected by a communications facilities or links. Network connections can be of a permanent nature, such as via cables, or can be of a temporary nature, such as connections made through telephone or other communication links. Networks vary in size, from a local area network (LAN) consisting of a few computers and related devices, to a wide area network (WAN) which interconnects computers and LANs that are geographically dispersed. An internetwork, in turn, is the joining of multiple computer networks, both similar and dissimilar, by means of gateways or routers that facilitate data transfer and conversion from various networks. A well-known abbreviation for internetwork is "internet." As currently understood, the capitalized term "Internet" refers to the collection of networks and routers that use a Transmission Control Protocol/Internet Protocol (TCP/IP) to communicate with one another.
A representative section 40 of the Internet is shown in FIG. 1 (Prior Art) in which a plurality of local area networks (LANs) 44 are connected by routers 42. The routers 42 are generally special purpose computers used to interface one LAN to another. Communication links within the LANs may be twisted wire pair, or coaxial cable, while communication links between networks may utilize 56 Kbps analog telephone lines, 1 Mbps digital T-1 lines and/or 45 Mbps T-3 lines. It will be appreciated that the Internet comprises a vast number of such interconnected networks and routers and that only a small, representative section of the Internet is shown in FIG. 1.
The Internet has recently seen explosive growth by virtue of its ability to link computers located throughout the world. In conjunction, the number of information services available on the Internet has grown significantly. For example, such services include electronic mail, Usenet (a collection of news groups dedicated to specific topics, Gopher (an information retrieval system created by the University of Minnesota), bulletin boards and the World Wide Web (WWW). Information provided by these services are transferred via the Internet using communication protocols that are designed specifically for the requirements of the particular service and used on top of TCP/IP to transfer information. For example, hypertext documents provided by the World Wide Web are transferred using a protocol known as HyperText Transfer Protocol (HTTP). Electronic mail can be transferred using the Simple Mail Transfer Protocol (SMTP), the Post Office Protocol-Version 2 (POP2) or the Post Office Protocol-Version 3 (POP3). Although HTTP, SMTP, POP2 and POP3 are mentioned here, those of ordinary skill in the art will appreciate that these protocols are only a representative sample of the plethora of protocols used to transfer information via the Internet and that new protocols and services are being added to the Internet each day.
In summary, the Internet is a conduit of information and services to any one of the smaller LANs or WANs belonging to it. The proliferation of information and services on the Internet has created the need for a method and apparatus to manage the communication of the information and services between the Internet and its member intranetworks. The method and apparatus for managing such communication should be capable of monitoring and logging the transmission of data packets between the intranetwork and the Internet. In addition, the method and apparatus should be capable of setting rules for the users of computers connected to the intranetwork that deny or allow access to certain Internet resources, e.g., denying or allowing access to certain WWW sites, denying or allowing retrieval of files from the Internet having certain file extensions, and denying or allowing the transfer of data to destinations in the intranetwork based on the type of protocol used to transfer the data. As described in the following, the present invention provides a method and apparatus that meet these criteria and solves other shortcomings in the prior art.